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The index page for all Programs
on the site?

The DFF Play CD?
Zipped file DFF
Play CD.zip contains executable version of about 75 of the 200+ programs from the site,
mostly those I particularly liked or thought would be of widest interest
for non-programmers. The file is rather large, about 20mb..

Anything
else?

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That's OK - the executable
version for any puzzle or game you find here is available
for download. Just scroll down to the bottom of most any
description page and you'll find a "Download executable"
link. Downloaded programs are in "zipped" format to
reduce size and may require an "unzipper" program
unless you are running Win XP or later. Here's
a link to a free one.

Check out the Most
Popular Downloads from DFF (updated weekly)

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Take
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Notes for
Teachers

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WHAT'S NEW
July 16, 2008: As a programmer, I have a standing
interest in how our brains get programmed; i.e. how we learn.
Any intellectual problem I can solve, I should be able to teach my "computer
brain" to solve. This has usually been the case, but after
40+ years of programming, the difficulty in doing so still surprises me.
Today's program Digital Position
Problem Solver is the latest example. It takes text problems
with phrases describing the relationships between the digits of an integer
(e.g. "the first digit is two less than the second") and figures out what
integer is being described. I was testing the 11th problem
before realizing that my "teaching" had overlooked something. The
problem sentence was: The fourth digit is one-fourth of the fifth.
Oops; "fourth" can be a position and a denominator! It is clear
to us humans that the relationship being described is "Fourth = 1/4*Fifth".
Problem 11 is still unsolved by the program until I figure out how I know
how to solve it and then how to "retrain" the program.
No wonder I love this stuff!
July 12, 2008: A minor update to the
DelphiForFun Library file,
DFFLibV11.zip, was posted this evening. with a few
changes. Some of these have been previously applied to version 10
without notice but it seemed time to catch up and document them.
DFFLIBV11 contains the following changes:
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In the DFFUtils unit a new routine,
IntToBinaryString, has been added to produce a display
(printable) binary representation of an integer. |
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UTGraphSearch unit cures a memory leak with a new "Clear"
method that frees nodes when it is called. |
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The UBigIntsV3 big integers has a corrected
Mult procedure to multiply a big integer by a 64 bit (Int64)
integer. In the old version, negative smaller Int64 integers (less
than 232-1) were treated as positive. |
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In the Mathslib unit the NbrFactors function
(number of factors for an integer) returned an incorrect value in some
cases. Long time contributor Charles Doumar found and submitted the
corrected version. |
I'm working on a new story problem solver which reads the text
and solves "digit relationship" problems like:
"Find a five-digit number in which the
first digit is double the second, the third digit is two less than the second,
the fourth digit is the sum of the second and third, and the last digit is one
less than the first. The sum of all the digits is 19."
The program is running for half a dozen samples, but I still
need to add a few more and do some documentation. Stay tuned.
I watched our 4 year old grandson continuously revising and honing his language
skills all this week. If only I could get my language processing programs
do the same, then we would have something special!
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| Panmagic Square: Columns, rows, 2 full diagonals and
8 broken diagonals all sum to 65. |
July 3, 2008: Generating a magic square of a
given size is not too difficult, especially if it has an odd number of cells
per side. Generating a lot of them is not so easy. A
viewer wrote a while ago asking about computing the amount of water that a
magic square would hold if each cell became a column with its height equal
to the value of the the cell. Might be an interesting problem to work
on, but we need some samples for testing. Today's first attempt,
PanMagic Squares, will
generate 115,000 or so 5x5 squares with a special "panmagic" property.
There are reported to be a few million order 5 magic squares altogether.
Hmmm, someone must know how to create them all.
Oh, by the way, the commonly reported total number of
different 5x5 panmagic squares is 28,800, so I may be all wet here.
I'm sure to hear more about this.
July 1, 2008: A small change to our
Cutting Stock program was posted
this evening. When multiple stock lengths were available, the summary
results grid could list the stock amount used and cost in a row that
associated it with the incorrect length and cost per piece data. The
problem has been corrected.
June 22, 2008: We're back! Home again
after 60 days of European travel. Stops included Germany,
Netherlands, a cruise (with stops in Turkey, Italy, and Spain), Switzerland,
France, Ireland, and Germany for a few days before flying home. We got
to spend part of the time with children and grandchildren but all in all, 60
days is too long to be away from the home we love here in Virginia. We
enjoyed the flowers and outdoor hikes, but museums, old churches, and
castles tend to become a blur after awhile. Europe has a
longer history than we have here in the States and Europeans have a greater
sense of their history. But we still feel fortunate to live in
the USA and are glad to be back home where the roads are well signed, where
a double bed is not two twin beds pushed together, where a Big Mac hamburger
costs $3 not €3, and where that evil
invention, the duvet, is rarely seen.
I had a few dozen DFF emails waiting for me when we got
home. I think I have answered those needing responses, so if you
wrote and did not receive a reply, please write again.
One question relating to the
Monitor off
program led to a small change which I tested on my Dell XPS laptop.
Monitor Off uses the Pause key to turn the monitor off or on, but the XPS
documentation did not specify what key combination is needed to generate the
pause key code. I posted Key
Scan Codes program today as a result of the investigation. It
displays key values for pressed keys which generate a character, or key
names for those which do not. By the way, on Dell XPS laptops the Fn
key and the Insert key combination generates Pause. Also by the
way, it looks like Monitor Off is not working under Vista, but that's a
problem for another day.
The WHAT'S NEW Archives
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